lib/Support/Compression.cpp

   1 //===--- Compression.cpp - Compression implementation ---------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 //  This file implements compression functions.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "llvm/Support/Compression.h"
  14 #include "llvm/ADT/SmallVector.h"
  15 #include "llvm/ADT/StringRef.h"
  16 #include "llvm/Config/config.h"
  17 #include "llvm/Support/Compiler.h"
  18 #include "llvm/Support/Error.h"
  19 #include "llvm/Support/ErrorHandling.h"
  20 #if LLVM_ENABLE_ZLIB == 1 && HAVE_ZLIB_H
  21 #include <zlib.h>
  22 #endif
  23
  24 using namespace llvm;
  25
  26 #if LLVM_ENABLE_ZLIB == 1 && HAVE_LIBZ
  27 static Error createError(StringRef Err) {
  28   return make_error<StringError>(Err, inconvertibleErrorCode());
  29 }
  30
  31 static StringRef convertZlibCodeToString(int Code) {
  32   switch (Code) {
  33   case Z_MEM_ERROR:
  34     return "zlib error: Z_MEM_ERROR";
  35   case Z_BUF_ERROR:
  36     return "zlib error: Z_BUF_ERROR";
  37   case Z_STREAM_ERROR:
  38     return "zlib error: Z_STREAM_ERROR";
  39   case Z_DATA_ERROR:
  40     return "zlib error: Z_DATA_ERROR";
  41   case Z_OK:
  42   default:
  43     llvm_unreachable("unknown or unexpected zlib status code");
  44   }
  45 }
  46
  47 bool zlib::isAvailable() { return true; }
  48
  49 Error zlib::compress(StringRef InputBuffer,
  50                      SmallVectorImpl<char> &CompressedBuffer, int Level) {
  51   unsigned long CompressedSize = ::compressBound(InputBuffer.size());
  52   CompressedBuffer.reserve(CompressedSize);
  53   int Res =
  54       ::compress2((Bytef *)CompressedBuffer.data(), &CompressedSize,
  55                   (const Bytef *)InputBuffer.data(), InputBuffer.size(), Level);
  56   // Tell MemorySanitizer that zlib output buffer is fully initialized.
  57   // This avoids a false report when running LLVM with uninstrumented ZLib.
  58   __msan_unpoison(CompressedBuffer.data(), CompressedSize);
  59   CompressedBuffer.set_size(CompressedSize);
  60   return Res ? createError(convertZlibCodeToString(Res)) : Error::success();
  61 }
  62
  63 Error zlib::uncompress(StringRef InputBuffer, char *UncompressedBuffer,
  64                        size_t &UncompressedSize) {
  65   int Res =
  66       ::uncompress((Bytef *)UncompressedBuffer, (uLongf *)&UncompressedSize,
  67                    (const Bytef *)InputBuffer.data(), InputBuffer.size());
  68   // Tell MemorySanitizer that zlib output buffer is fully initialized.
  69   // This avoids a false report when running LLVM with uninstrumented ZLib.
  70   __msan_unpoison(UncompressedBuffer, UncompressedSize);
  71   return Res ? createError(convertZlibCodeToString(Res)) : Error::success();
  72 }
  73
  74 Error zlib::uncompress(StringRef InputBuffer,
  75                        SmallVectorImpl<char> &UncompressedBuffer,
  76                        size_t UncompressedSize) {
  77   UncompressedBuffer.resize(UncompressedSize);
  78   Error E =
  79       uncompress(InputBuffer, UncompressedBuffer.data(), UncompressedSize);
  80   UncompressedBuffer.resize(UncompressedSize);
  81   return E;
  82 }
  83
  84 uint32_t zlib::crc32(StringRef Buffer) {
  85   return ::crc32(0, (const Bytef *)Buffer.data(), Buffer.size());
  86 }
  87
  88 #else
  89 bool zlib::isAvailable() { return false; }
  90 Error zlib::compress(StringRef InputBuffer,
  91                      SmallVectorImpl<char> &CompressedBuffer, int Level) {
  92   llvm_unreachable("zlib::compress is unavailable");
  93 }
  94 Error zlib::uncompress(StringRef InputBuffer, char *UncompressedBuffer,
  95                        size_t &UncompressedSize) {
  96   llvm_unreachable("zlib::uncompress is unavailable");
  97 }
  98 Error zlib::uncompress(StringRef InputBuffer,
  99                        SmallVectorImpl<char> &UncompressedBuffer,
 100                        size_t UncompressedSize) {
 101   llvm_unreachable("zlib::uncompress is unavailable");
 102 }
 103 uint32_t zlib::crc32(StringRef Buffer) {
 104   llvm_unreachable("zlib::crc32 is unavailable");
 105 }
 106 #endif